TOKYO, Japan (AP) -- Nationalist Shinzo Abe becomes Japanese Prime Minister with a promise to create a more assertive Japan and give its military a larger international role.

Abe's Cabinet picks are expected to reflect his aims for a diplomatically and economically strong Japan.

But the surge in Japan's assertiveness coincides with the spectacular rise of China's clout in the region -- risking ever greater competition over resources, political influence and military stature in an already unstable region.

Beijing reacted testily to Abe's landslide victory in last week's ruling party elections, issuing a terse statement urging the new leader to improve frayed bilateral relations.

Despite that, it's still not clear what effect Abe's rise will have. His nationalist credentials could give him room domestically to reach out to China by shielding him from charges of weakness from Japan's increasingly vocal right.

He's hinted at that already, publicly acknowledging the need to strengthen ties with China. A top Abe aide on Sunday said setting up a meeting with Chinese leader Hu Jintao was high on the new leader's agenda.

Still, elements of Abe's program could complicate the road to better relations.

More prominent role for military.Though soft-spoken, Abe has some bold goals: He promises to raise Japan's international stature and revise the country's pacifist constitution to give the military a more prominent role.

He has also pledged to bring more patriotism to schools, and boost Japan's military alliance with the United States -- both sore points with the Chinese who feel that Japanese textbooks gloss over Japan's wartime atrocities, and that the U.S.-Japan alliance is aimed at containing Beijing.

Those stands have raised concerns in the region.

"Abe's rhetoric is very dangerous, given China's growing clout in the region," said Hiro Katsumata, a research fellow at the Institute of Defense and Strategic Studies in Singapore.

"It could prompt China to become coercive, and take a more hard-line approach," Katsumata said. "Today's China won't back down."

The origins of that standoff predate Abe. Prime Minister Junichiro Koizumi has already raised Japan's military visibility by dispatching troops to assist U.S.-led reconstruction efforts in Iraq and sending ships to the Indian Ocean to provide fuel for coalition forces in Afghanistan.

Koizumi also insisted on paying his respects at Tokyo's Yasukuni war shrine, which has strong links to Japan's right wing, enraging China and others who say Japanese leaders have not fully atoned for the country's wartime aggression. Summit-level meetings between the two countries have been suspended for over a year.

Abe has visited the shrine on many occasions, but has shrewdly kept mum on whether he will visit as prime minister, thereby silencing -- for now -- both pacifists and the right wing.

Revisionist history textbooks.Still, he could soon be hindered by his conservative views of Japanese history, said Lu Xijin, professor of international relations at Daito Bunka University in Tokyo. Abe has supported revisionist history textbooks, for instance.

"The major obstacle to Japan's Asia policy has been differing perceptions of the past," Lu said. "It would negatively affect China-Japan relations if Abe prioritizes his own principles."

Finding common ground will be difficult also because what's at stake isn't just bilateral relations, but the countries' relative standing in the region, as well cooperation on regional hot spots like North Korea.

When Pyongyang test-fired seven missiles in July, Tokyo -- spearheaded by Abe -- slapped immediate sanctions on the North and pushed for a punitive resolution at the U.N. Security Council. China protested that Japan was overreacting, and Tokyo was finally forced to settle on a weaker resolution.

The spat at the U.N. came after China, a veto-yielding, permanent member of the Security Council, helped wreck Japan's hopes of joining that privileged club. A sulky Japan has threatened to reduce its U.N. dues and demanded that China increase its own contribution.

Tokyo and Beijing have also clashed over who will take the lead in regional economic integration, with Japan pushing for a wider free trade zone stretching from India and Australia to dilute Beijing's rising economic power.

At odds with Beijing.And the two are at odds as they scramble for energy, vying over gas and oil resources in a disputed section of the East China Sea, a pipeline from Siberia in Russia, and secure passage through the Malacca Straits, the narrow Southeast Asian causeway through which virtually all Middle Eastern and African oil headed to East Asia moves.

Meanwhile, both sides have been flexing their military muscle. China has announced double-digit spending increases for its 2.5 million-member military nearly every year since the early 1990s, prompting Japan's Defense Agency to list China's military expansion as a top security concern in the region.

While Japan hasn't increased spending, the Cabinet last month endorsed a bill to upgrade the Defense Agency to a full-fledged ministry to reflect the growing role of the country's military.

Tokyo recently wrapped up a historic non-combat troop deployment to Iraq -- the country's first to a combat zone in 60 years -- and is also in the midst of a sweeping realignment of the 50,000 U.S. troops stationed in Japan to assume a more prominent role in regional security.

Koizumi left the Prime Minister's Office Tuesday with a bouquet of flowers in his hands as supporters cheered, ending more than five years in office marked by far-reaching changes such as passage of legislation to privatize the postal service.

"There is no end to reform," he said in a parting statement. "I hope that the public will work with the new prime minister to believe in Japan's future and continue the reform with courage and hope."